Is there a query for this

[H. Druss]

Hi All
Front end vb6, back end Access.
Program makes reservations for my library.
4 rooms, length of reservation will be in half hour increments
I need to be sure two events are not booked with overlapping times.
Right now I retrieve a recordset as follows

Date, Room, StartTime, StopTime ( sorted by StartTime)
So a typical recorset with two events scheduled might look like:

12/5/2008 Druker Auditorium 9:00am 10:30am
12/5/2008 Druker Auditorium 1:30pm 4:00pm

Would there be any type of query to be sure another reservation would not
confilct.
e.g. A person would try to book an event from 3:00pm until 6:00pm


Thank you
Harold

 

[Allen Browne]

The logic is that 2 events clash if:
A starts before B ends, AND
B starts before A ends.

You can see this meets all cases if you diagram it on a piece of paper,
e.g.:
A ------------------------------
B ------------------
or:
A ----------------------------------
B --------
and so on.

Use record-level validation (the Form_BeforeUpdate event if you were working
in Access) to see if there is any other record for which this condition is
met

 

[H. Druss]

Hi Allen
Perfect! I've applied the logic to a vb Function.
Thank you very much.
Harold